The Collaborative International Dictionary of English v.0.48:
Ad hominem \Ad hom"i*nem\ [L., to the man.] A phrase applied to an appeal or argument addressed to the principles, interests, or passions of a man. [1913 Webster]WordNet (r) 3.0 (2006):
ad hominem adj 1: appealing to personal considerations (rather than to fact or reason); "ad hominem arguments"